Display screen or portion thereof with an animated graphical user interface



FIG. 1 is a front view of a first image of a display screen or portion thereof with an animated graphical user interface showing our new design;

FIG. 2 is a front view of a second image thereof;

FIG. 3 is a front view of a third image thereof;

FIG. 4 is a front view of a fourth image thereof;

FIG. 5 is a front view of a fifth image thereof;

FIG. 6 is a front view of a sixth image thereof; and,

FIG. 7 is a front view of a seventh image thereof.

The appearance of the transitional image sequentially transitions between the images shown in FIGS. 1 through 7. The process or period in which one image transitions to another image forms no part of the claimed design.

The dash-dot broken line showing of a portion of a display screen in FIGS. 1-7 represents environmental subject matter and forms no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with an animated graphical user interface, as shown and described. 